Laminate flooring usually comprising rectangular floor panels with a core of a 6-12 mm fibre board, a 0.2-0.8 mm thick upper decorative surface layer of laminate and a 0.1-0.6 mm thick lower balancing layer of laminate, plastic, paper or like material. A laminate surface comprises a printed melamine impregnated paper, which is pressed with an embossed sheet. The most common core material is fibreboard with high density and good stability usually called HDF—High Density Fibreboard. Sometimes also MDF—Medium Density Fibreboard—is used as core.
Traditional laminate floor panels of this type have taken a large market share mainly due to the fact that advanced printing and pressing technology has made it possible to make very natural copies of mainly wood parquet floorings. Laminate floorings look like wood, but are more durable and less expensive than wood floorings.
In addition to such traditional floors, which have been installed with a tongue and groove joint and with glue, floor panels have been developed which do not require the use of glue and instead are joined mechanically by means of so called mechanical locking systems.
These systems comprise locking means, which lock the panels horizontally and vertically. The mechanical locking systems are usually formed by machining of the core of the panel. Alternatively, parts of the locking system can be formed of a separate material, for instance aluminium or HDF, which is integrated with the floor panel, i.e. joined with the floor panel in connection with the manufacture thereof.
The main advantages of floating floors with mechanical locking systems are that they are easy to install. They can also easily be taken up again and used once more at a different location.
Definition of Some Terms
By “horizontal plane or principal plane” is meant a plane, which extends parallel to the outer part of the surface layer. Immediately juxtaposed upper parts of two adjacent joint edges of two joined floor panels together define a “vertical plane (V)” perpendicular to the horizontal plane. By “horizontally” is meant parallel to the horizontal plane and by “vertically” parallel to the vertical plane
By “locking systems” are meant co acting connecting means, which connect the floor panels vertically and/or horizontally. By “mechanical locking system” is meant that joining can take place without glue.
By a “discontinuous surface layer and core” is meant the surface layer and core of two elements connected to each other to form one panel or two panels connected to each other to form a floor and consequently the core and surface layer of the connected elements and the panels respectively is discontinuous. A joint is detectable between the two elements or panels at the discontinuity.
Known Techniques and Problems Thereof
Printing and pressing technology have in recent years been developed further and very natural copies of stone, tiles and parquet strips have been introduced on the market.
There are however a lot of designs and patterns which are not possible to produce and install with the present printing, pressing and mechanical locking technology.
Most designs which contain patterns or structures where parts have to be aligned with the format of the floor panel are difficult to produce since swelling and shrinking of the printed paper and the positioning of the printing paper and the press sheet are difficult to control. Joints that cross a specific pattern, with parts designed to be one unit, give an unnatural appearance.
It is known that some advanced patterns could be produced with individual rectangular small floor panels, which could be connected to floor units. Such patterns and floor panels are described in WO 03/089736. This known technology has the disadvantage that the connection between the floor panels is expensive and complicated to produce, especially when a floor unit comprises several small panels. It would be a great advantage if individual floor elements could be produced and connected to larger floor panels in more cost efficient way.